1. Technical Field
The present invention relates to a substrate processing apparatus processing substrates.
2. Description of Related Art
As higher density tendency is progressed, in a semiconductor device such as DRAM, for example, a high dielectric constant film (High-k film) containing hafnium (Hf) element and zirconium (Zr) element has been used, as a gate insulating film and a capacitor insulating film. For example, this is because a HfO2 film having a film thickness of 1.6 nm can have a high dielectric constant equivalent to that of a SiO2 film having a film thickness of 4.5 nm. As a method of forming the high dielectric constant film containing Hf element and Zr element, for example an ALD (Atomic Layer Deposition) method has been used, for alternately supplying vaporized gas generated by vaporizing an organic compound (liquid source) such as TEMAH (Hf[N(CH3)CH2CH3]4:tetrakis methyl amino hafnium) and TEMAZ (Zr[N(CH3)CH2CH3]4:tetrakis ethyl methyl amino zirconium) by a vaporizer, and oxide gas such as ozone (O3), into a processing chamber in which substrates such as silicon wafers are stored.
When the high dielectric constant film is formed by using the organic compound such as TEMAH and TEMAZ, carbide is remained in the vaporizer, or by-products including impurities of the vaporized gas, such as an oxide of the vaporized gas, are sometimes formed within a piping connecting inside of the vaporizer and inside of the processing chamber. Possibly, such carbide and oxide can be factors of generating particles (foreign matters), thereby deteriorating a production yield of the semiconductor device. Further, the organic compound such as TEMAH and TEMAZ are easy to react with moisture. Therefore, when purge of the inside of the vaporizer and the inside of the piping executed for removing moisture is insufficient after the vaporizer and the piping are exchanged, or when the vaporizer and the piping are unevenly heated, the moisture remained in the vaporizer and the piping and the organic compound are reacted, to thereby generate the particles in some cases.
In order to suppress diffusion of the particles generated in the vaporizer and the piping, into the processing chamber, in a conventional substrate processing apparatus, a filter is provided to the piping that connects the vaporizer and the processing chamber. However, with this structure, the inside of the vaporizer and the inside of the piping are exposed to the atmosphere when the filter is exchanged, and the moisture is adhered to inner walls thereof, resulting in the generation of the particles in some cases. A method of exchanging a part of a piping member exposed to the atmosphere during exchange of the filter can also be considered. However, this method involves a problem that the time required for an exchange work of the filter is increased and a cost is also increased. Particularly, it is sometimes also necessary to install/remove a heating heater provided to a periphery of the piping, when the piping member, etc, is exchanged, thus involving a problem that the time required for the exchange work of the filter is increased and the cost is also increased.